There's a deadly microbe loose on the land, and medical detectives are hot on its trail

Tammy Lowery couldn't see the blood vessels rupturing in her gut, but the way she was feeling, she didn't have to. Lowery had been sick for five days, growing steadily worse as the week wore on. First had come the stomach pains. Then the bloody diarrhea. Then the paralyzing cramps. She had laid off food for a while, figuring the problem would pass. It didn't. Finally, as July 4 approached--when Lowery should have been at the Alpine, Wyo., gift shop where she works, preparing for the crush of campers and tourists who make the Independence Day weekend such a busy one--she...